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What is making the Glow-worms Glow?

17 August 2011

What do you think astronomers call the green thing in this photo? If you guessed “blob”, then you’re right! Well, if we’re being technical, the full name for this type of object is a “Lyman-alpha blob”.

These blobs are incredibly rare and very far away in the Universe. They are also some of the biggest objects in the Universe – these gigantic clouds of gas can be up to a few times bigger than the size of our galaxy, the Milky Way! Like a swarm of glow-worm insects, these blobs shine brightly. But what is causing the blobs to glow is a mystery to astronomers.

One idea is that they glow when gas heats up as it is pulled in by a blob’s powerful gravity. Another idea is that they are glowing because there are bright galaxies inside the blobs.

Now, using a powerful telescope called the Very Large Telescope, which is based in a country in South America called Chile, astronomers are a step closer to solving the mystery. By carefully studying the properties of the light given off by the blob shown in this photo, astronomers know that this one glows because it contains bright galaxies.

The astronomers will now study more of these objects to see if galaxies are responsible for making all blobs glow. Astronomers don’t like to jump to conclusions based on just one finding!

Cool fact: The first Lyman-alpha blobs were discovered only 12 years ago! What new objects in space will we discover in the next 12 years?

This is a kids version of ESO Press Release eso1130.